Many people purchase hot beverages “to go”, such as coffee, café latte, tea, chai and similar drinks at coffee shops, convenience stores, espresso stands and the like. The hot beverages are generally provided in a plastic-coated cardboard container, generally with a plastic lid. Many purchasers prefer to drink their beverages at a leisurely pace while traveling in an automobile, commuting to work, or at work or home. Since such drinks may consist of 16 oz. or more in quantity, it is frequently desirable to consume them over a period of 30 minutes or more. The problem is that the beverages cool off fairly rapidly, and are no longer as desirable or satisfying as when originally purchased.
Styrofoam containers are occasionally used to serve hot beverages, and may provide some thermal insulation to retard cooling, but many hot-beverage aficionados believe the styrofoam imparts an unpleasant side-taste to the beverage. In addition, there is widespread and increasing resistance to the use of styrofoam on environmental grounds. Establishments catering to the serious hot-beverage consumers invariably use the plastic-coated cardboard containers.
There is a large variety of insulated containers available, and many people simply transfer their hot beverages from the ubiquitous cardboard containers to the insulated containers, and consume their beverage at their leisure. This can be quite effective in maintaining the beverage near the optimum temperature, but requires carrying the insulated container to the beverage shop, or having it available nearby. It also necessitates washing the insulated container out after use. The convenience of the cardboard container, which can be discarded after the beverage is consumed, is lost.
Also widely available are small hot-plates designed to keep beverages in a container at or near optimum drinking temperature. Such hot plates, which are designed for use on a desk or counter, work quite well with conventional metal, plastic or ceramic beverage containers, but are not very effective when used with the conventional “take-out” cardboard container; cardboard is a relatively poor heat-transfer substance, and the bottom of the beverage-containing part of the container is recessed inside the bottom of the container walls, and does not contact the heated surface of the hot plate.
Beverage containers with provisions for electrically heating the contained beverage are described by, for example, Dam, U.S. Pat. No. 6,121,585. An electrically heated beverage container designed to plug into an automobile cigarette lighter is marketed by The Johnson Smith Company, Bradenton, Fla. as their “Clever Cup”, Item #51102. A container designed for infant milk or formula, in which the fluid can be heated by electrical or exothermic reaction, is taught by Teglbjarg, U.S. Pat. No. 6,123,065. Also known in the art are electrically heated devices for warming infant nursing bottles or food containers, such as the “Baby Bottle and Food Warmer”, Item No. 09234, distributed by One Step Ahead/Leaps And Bounds Co., of Lake Bluff, Ill.; this device is essentially a small electrically heated water bath in which food or drink containers are partially immersed.
Beverage containers with provisions for heating the contained beverage by burning fuel or by mixing substances which react exothermically are taught by, for example, Pimm et al, U.S. Pat. No. 5,148,688 and Tenenboum et al, U.S. Pat. No. 6,267,110. A commercially available baby-bottle warmer utilizing an exothermic heating element is distributed by One Step Ahead/Leaps And Bounds Co., of Lake Bluff, Ill. as its “Reusable On-The-Go Bottle Warmer”, Item No. 06918.
All of these aforementioned devices involve the use of a specialized container for the beverage, and none could be adapted for slip-on use with the plastic-coated cardboard hot-beverage containers in widespread use. A diligent search of the patent literature failed to identify any device which could be used as a slip-on warmer to keep a beverage in a disposable container warm.
A device which could slip over a cardboard hot-beverage container and maintain the beverage at the optimum temperature for consumption over extended periods, and which would slip off the container when empty, allowing the container to be discarded, would be very useful. Ideally, the device should be sufficiently thin so that, when slipped onto beverage-container it would not prevent the container plus device from fitting easily in automobile cup-holders or similar receptacles. The device should be compact, so that it could easily be stowed in a pocket or purse when not in use.
The present invention provides such a device.